Decomposition of Organic Wastes: Thermal Analysis and Evolution of Volatiles

In this chapter, the thermal decomposition of organic wastes is analyzed considering different approaches. Firstly, a brief revision of the processes related (pyrolysis, combustion, and gasification) is analyzed and the influence of the operating conditions (heating rate, temperature, and pressure) is also considered. Secondly, the thermal analyses: thermogravimetry (TG), derivative thermogravimetry (DTG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC) are presented. Thirdly, the use of TG/DTG to study the decomposition of the wastes is reviewed, analyzing many recent contributions with different goals. Fourthly, the analysis of the volatilized fraction and the kinetics of the process are discussed, with special attention to the reactions involved. Fifthly, the evolution of volatiles is discussed considering different apparatus: TG/MS (thermal analysis/mass spectrometry), TG/FTIR (thermal analysis/infrared spectroscopy), TG/GC/MS (thermal analysis/gas chromatography/mass spectrometry) and other complementary apparatus, such as pyrolyzers and laboratory reactors. Lastly, the thermal effects measured by DTA and DSC are analyzed.